Tipping the Webscale with XMPP & WebSockets
Sonny Scroggin email/xmpp: sonny@scrogg.in + github/twitter: @scrogson
Nashville, TN
openstack hosted private cloud // hybrid cloud bluebox.net
WHAT WE'LL COVER INTRODUCTION TO THE XMPP PROTOCOL SERVERS CLIENTS COMPONENTS HOW TO APPLY
EXTENSIBLE MESSAGING & PRESENCE PROTOCOL
CORE SERVICES Channel Encryption Authentication Presence Roster Messaging (one-to-one, multi-party) Service Discovery Notifications (Publish/Subscribe) Capabilities Advertisement Data Forms Peer-to-Peer Media Sessions
WHY XMPP? Why XMPP? Open - free, public, and easy to understand Standard - RFC 6120 / 6121 / 6122 Proven - first developed in 1998 and is very stable Decentralized - similar to email, run your own server Secure - SASL and TLS built-in Extensible - build on top of the core protocols
WHO USES IT? Apple - imessage, Push Notifications, Bonjour Google - GoogleTalk, Push Notifications Cisco - Webex Facebook - chat WhatsApp - started with ejabberd Chesspark - online chess game
ROUTING / ADDRESSING
ROUTING / ADDRESSING JID (Jabber ID) - addressing similar to email Bare - <user>@<server> Full - <user>@<server>/<resource> Resource - allows multiple sessions per user Automatically generated by the server if not specified Messages can be addressed to either the bare JID or full JID Messages to the bare JID route to the full JID with the highest priority
BASIC CONNECTION LIFECYCLE
BASIC CONNECTION LIFECYCLE Client initiates a TCP connection to the server Sends stream header Negotiates stream features and authentication mechanisms The client binds to a resource The client sends presence to the server The client requests its roster The client sends and receives messages to/from others The client ends the session and closes the connection
COMMUNICATION PRIMATIVES
COMMUNICATION PRIMATIVES XML Stanzas Fragments of XML sent over an XML stream <message/> <presence/> <iq/>
COMMUNICATION PRIMATIVES Common Attributes to: specifies the JID of the intended recipient from: specifies the JID of the sender type: specifies the purpose or context of the message xml:lang: specifies the default language of any such human-readable XML character data id: used by the originating entity to track any response or error stanza that it might receive in relation to the generated stanza from another entity
STANZAS: MESSAGE The <message/> stanza is a "push" mechanism. One entity pushes information to another entity, similar to the communications that occur in a system such as email. The payload in the case of instant messaging is a <body/> element, but it can also include any other custom elements to extend the protocol. <message to="romeo@im.montague.lit" id="sa7f8df" type="chat" xml:lang="en"> <body>where art thou, Romeo?</body> </message> NOTE: Juliet's server will add the "from" attribute when routing the message.
STANZAS: PRESENCE The <presence/> stanza is a "broadcast" or "publish/ subscribe" mechanism. Multiple entities receive information (in this case, network availability information) about an entity to which they have subscribed. Sets and shows the availability of the entity that is connected. Announce availability on the server <presence/>
STANZAS: PRESENCE Announce you're away <presence> <show>away</show> </presence> Do not disturb <presence> <show>dnd</show> <status>working hardcore...</status> </presence> Going offline <presence type="unavailable"/>
STANZAS: PRESENCE Subscriptions Juliet requests a subscription to Romeo's presence <presence to="romeo@im.montague.lit" type="subscribe"/> Romeo gladly excepts <presence to="juliet@im.capulet.lit" type="subscribed"/>
STANZAS: IQ The <iq/> stanza is a "request/response" mechanism, similar in some ways to HTTP. Enables an entity to make a request of, and receive a response from, the server or another entity. Request type is either "get" or "set". Response type is either "result" or "error". Service discovery Juliet requests Romeo's vcard <iq to="romeo@im.montague.lit" type="get" id="s8f7"> <vcard xmlns="vcard-temp"/> </iq>
STANZAS: IQ Romeo's server responds <iq to="juliet@im.capulet.lit/balcony" from="romeo@im.montague.lit" type="result" id="s8f7"> <vcard xmlns="vcard-temp"> <EMAIL> <USERID>romeo@montague.lit</USERID> </EMAIL> <FN>Romeo Montague</FN> </vcard> </iq>
STANZAS: IQ Roster request <iq to="im.capulet.lit" type="get" id="s8f7"> <query xmlns="jabber:iq:roster"/> </iq> Server response <iq to="juliet@im.capulet.lit/balcony" type="result" id="s8f7" from="im.capulet.lit"> <query xmlns="jabber:iq:roster"> <item jid="romeo@im.montague.lit" name="romeo Montague" subscription="both"> <group>lover</group> </item> </query> </iq>
SERVICE DISCOVERY
SERVICE DISCOVERY Query clients or servers about features/capabilities Enables you to find out which features are supported by another entity, as well as any additional entities that are associated with it (e.g., rooms hosted at a chat room service). disco#info query <iq to="juliet@im.capulet.lit/balcony" type="get" id="s8f7"> <query xmlns="http://jabber.org/protocol/disco#info"/> </iq>
SERVICE DISCOVERY disco#info response <iq from='juliet@im.capulet.lit/balcony' to='romeo@im.montague.lit/library' type='result' id='a2a3'> <query xmlns='http://jabber.org/protocol/disco#info'> <identity category='client' type='pc' name='adium'/> <feature var='http://jabber.org/protocol/caps'/> <feature var='http://jabber.org/protocol/chatstates'/> <feature var='http://jabber.org/protocol/muc'/>... <feature var='http://jabber.org/protocol/muc#user'/> <feature var='http://jabber.org/protocol/xhtml-im'/> <feature var='http://jabber.org/protocol/commands'/> </query> </iq>
SERVICE DISCOVERY disco#items query <iq to="im.capulet.lit" type="get" id="s8f7"> <query xmlns="http://jabber.org/protocol/disco#items"/> </iq> disco#items response <iq from='im.capulet.lit' to='juliet@im.capulet.lit/balcony' id='1396' type='result'> <query xmlns='http://jabber.org/protocol/disco#items'> <item jid='conference.im.capulet.lit'/> <item jid='pubsub.im.capulet.lit'/> <item jid='vjud.im.capulet.lit'/> <item jid='im.capulet.lit' node='announce' name='announcements'/> <item jid='im.capulet.lit' name='configuration' node='config'/> <item jid='im.capulet.lit' name='user Management' node='user'/> <item jid='im.capulet.lit' name='online Users' node='online users'/> <item jid='im.capulet.lit' name='all Users' node='all users'/> </query> </iq>
SERVERS
SERVERS ejabberd https://github.com/processone/ejabberd The World's Most Popular XMPP Server Application Alexey Shchepin started ejabberd in November 2002 Written in Erlang Version 1.0 in December 2005 Supports most popular XMPP services Extremely flexible (gen_mod, ejabberd_hooks)
SERVERS MongooseIM https://github.com/esl/mongooseim Erlang Solutions forked ejabberd at version 2.1.8 OTP compliant project structure Improved the build process Removed obsolete/rarely used modules to reduce maintenance burden Reduction of runtime memory consumption Test coverage of the system according to corresponding RFCs and XEPs. MongooseIM provides high availability, ease of deployment, development, and reliability in production. It's aimed at large, complex enterprise level deployments where real-time communication is critical for business success.
CLIENTS
CLIENTS Stanza.io https://github.com/otalk/stanza.io Modern XMPP in the browser, with a JSON API. Stanza.io is a library for using modern XMPP in the browser, and it does that by exposing everything as JSON. Unless you insist, you have no need to ever see or touch any XML when using stanza.io. Useful when connecting directly to a websocket enabled XMPP server and you have built custom server modules to handle your business logic.
CLIENTS: STANZA.IO Example Echo Client var XMPP = require('stanza.io'); // if using browserify var client = XMPP.createClient({ jid: 'echobot@example.com', password: 'hunter2', }); transport: 'websocket', wsurl: 'wss://example.com:5281/xmpp-websocket' client.on('session:started', function () { client.getroster(); client.sendpresence(); }); client.on('chat', function (msg) { client.sendmessage({ to: msg.from, body: 'You sent: ' + msg.body }); }); client.connect(); Borrowed from the stanza.io README
CLIENTS Hedwig https://github.com/scrogson/hedwig XMPP Client/Bot Framework Hedwig is an XMPP client and bot framework written in Elixir. It allows you to build custom response handlers to fit your business logic. Simply configure Hedwig with credentials and custom handlers and you're set!
CLIENTS: HEDWIG Hedwig Client Configuration use Mix.Config alias Hedwig.Handlers config :hedwig, clients: [ %{ jid: "juliet@im.capulet.lit", password: "R0m30!" nickname: "romeosgirl", resource: "balcony", rooms: [ "lobby@conference.im.capulet.lit" ], handlers: [ {Handlers.Help, %{}}, {Handlers.GreatSuccess, %{}} ] } ]
CLIENTS: HEDWIG Example Handler defmodule Hedwig.Handlers.GreatSuccess do use Hedwig.Handler @links [ "http://mjanja.co.ke/wordpress/wp-content/uploads/2013/09/borat_great_success.jpg", "https://www.youtube.com/watch?v=r13riarkgo0" ] def handle_event(%message{} = msg, opts) do cond do hear ~r/great success(!)?/i, msg -> process msg true -> :ok end {:ok, opts} end def handle_event(_, opts), do: {:ok, opts} defp process(msg) do :random.seed(:os.timestamp) link = Enum.shuffle(@links) > List.first reply(msg, Stanza.body(link)) end end
COMPONENTS
COMPONENTS XEP-0114: Jabber Component Protocol Allows you to extend server functionality External - connects to server or vice versa Handshakes and authenticates with the server Can be written in any language Can interact on the whole domain or subdomain Can alter stanzas including the to/from attributes
PHOENIX Phoenix https://github.com/phoenixframework/phoenix Elixir Web Framework Phoenix is a web framework targeting full-featured, fault tolerant applications with realtime functionality. It has support for WebSockets baked-in.
PHOENIX Router defmodule MyApp.Router do use Phoenix.Router pipeline :browser do plug :accepts, ~w(html) plug :fetch_session end pipeline :api do plug :accepts, ~w(json) end scope "/", alias: MyApp do pipe_through :browser get "/pages/:page", PageController, :show resources "/users", UserController do resources "/comments", CommentController end end scope "/api", alias: MyApp.Api do pipe_through :api resources "/users", UserController end channel "xmpp", XMPPChannel end
IDEAS
IDEAS XMPP Server Hedwig Client XMPP Channel Phoenix WebSocket Client
DEMO?
Fragen?
Danke!